Solenoid



L. FUCHS Feb. 11, 1947.

SOLENOIDS Filed Sept. 21, 1944 Louis Fuc 1L6.

Patented Feb. 11, 1947 SOLENOID Louis Fuchs, -Hasbrouck Heights, N. J.,assignor to Bendix' Aviation N. J a corporation of Delaware Corporation,

Teterboro,

Application September 21, 1944, Serial No. 555,137

My invention relates to electromagnetic apparatus, and more particularlyto the mechanical construction thereof.

Electromagnets of the solenoid type are used extensively ininstallations of a character involving associated parts whereinvibrational and other disturbances are set up, which disturbances, whencommunicated to the solenoid assembly, tend to cause corresponding, butquite objectionable vibration and sometimes equally objectionablereciprocatory and/or rotary movements of the solenoid plunger with theresult that the sleeve, in which the plunger is mounted, becomes undulyworn within a relatively short period thereby necessitating replacement.

One of the objects of my invention is to provide a solenoid equippedwith means for counteracting the aforementioned tendency and forcontrolling the eifect thereof upon the solenoid plunger whereby wear onthe plunger sleeve is maintained at a minimum.

Another object of my invention is to provide a solenoid wherein theinter-relationship and the operation of the various components serve topreclude noise or chatter.

A further object of my invention is to provide a solenoid of theforegoing described character which is so constructed and arranged as topreclude removal, discharge or displacement of the plunger from withinthe solenoid while the latter is in assembled relation.

An important object of my invention is to provide a, solenoid of theforegoing described character which is imple in construction, durable inuse, eflicient in operation, economical in manufacture and relativelysilent when deenergized.

With the above and other objects in view, as will hereinafter appear,the invention consists in the combination, and arrangement of arthereinafter set forth and illustrated in the accompanying drawing, fromwhich the several features of the invention and the advantages attainedthereby will be readily understood by those skilled in the art.

Referring to the drawing wherein like reference characters designatelike parts throughout the several views,

Figure 1 is a perspective view of my invention.

Figure 2 is a sectional view taken on the line 2-2 of the Figure 1.

Figure 3 is a sectional view taken on the line 33 of Figure 2.

Figure 4 is a disassembled perspective view of the plunger andinterlocking pin.

In teaching my invention, as illustrated in the 4 Claims. (Cl. 175-341)drawing, I utilize a casing unit I0 comprising a cylindrical metallicshell or casing ll having an open end and provided with radiallydisposed flanges l2 adjacent said open end. The opposite end of thecasing i integrally formed with an end wall I 3 provided with a centralaperture in which is disposeda shank l4 formed on the adjacent radialouter end face of a fixed pole-piece or magnetic plug I5 disposedaxially within the casing and provided with a recessed frustumshapedinner end face 5. The shank I4 is formed on its outer end with acircumferential lip coacting with the outer end face to secure the plugto the end wall l3 and in fixed relation therewith. The circumferentialface of the casing, adjacent the margin of the end wall I3, is providedwith a hole H, the purpose of which will hereinafter become apparent.

A coil assembly unit 20 is arranged within the casing and isintroducible therein as a unit, and

'- which comprises a closure plate 2| transversing the open end of thecasing and provided with flanges 22 engaging flanges l2 and formed witha centrally disposed opening 23 and an outwardly disposed rib 24surrounding the opening, the latter having fixed therein one end of anonmagnetic guide sleeve 25 on which is mounted an exciting coil 26. Theopposite end of the sleeve 25 is provided with a collar 21 coacting withthe plate 2| to maintain the coil 26 therebetwcen, said collar beingconnected to one .lead wire (not shown) of the coil 26 and engaging thecasing ID to establish a ground connection between the coil and casing.The other lead wire 29 of the coil is insulated and extends through anotch (not shown) formed in the periphery of the collar and out of thecasing through the hole I! as depicted in the drawing.

The aforementioned opposite end of the sleeve 25 tightly embraces theplug l5 and forms a seal therewith to preclude the escape of airtherebetween from Within the sleeve for a .purpose hereinafter madeapparent. By thus disposing the plug within the sleeve, the plug servesto maintain centralization of the unit 20 within the casing. Aninterlocking element or pin 3| is disposed in parallel relation with thesleeve and extends axially through the rib 24 and plate 2| and theadjacent end face of the sleeve 25 for securing the sleeve to the plateagainst relative rotation, a side portion 32 of the pin projects andextends longitudinally within the bore of the sleeve 25.

A movable pole-piece or magnetic plunger 35 is slidably mounted withinthe sleeve and is provided with inner and outer end faces 36 and 3frespectively, the outer face fill having a diametrically reducedprojecting end section 36. The cir-. cumferential face 38 of the'plungeris formed with a longitudinal groove 39 terminating in spaced relationto the inner frustum-shaped end face 36 and which ,groove 39 receivesthe side portion 32 of-the pin 3 plunger relative to the sleeve 25 isprecluded. The confronting inner end faces 68' and 35 of the plug it andplunger 35 are formed with aligned sockets it receiving therein oppositeends of a coil spring ti which functions to urge the plunger away fromthe plug when the solenoid is deenergized thereby establishing an airchamber 32 between the plunger and plug as clearly illustrated in Figure2 of the drawing. Obviously,

i whereby rotation of the when the solenoid is energized, the plunger isactuated in a direction towards'the plug and air contained in thechamber d2, between the plunger and plug, is forced outwardly therefromabout and between the sleeve 25 and plunger 35 as hereinafter fullydisclosed, it being borne in mind that the plug it and sleeve 25 aretightly fitted to form aseal therebetween.

The diameter of the plunger 35 is such as to establish a relativelyclose fit of the plunger with the sleeve 25 and thus provide arelatively small circumspace or ring-like passage between the plungerand sleeve for the escape of air from the chamber 32. The inner end faceof the plunger is of a continuous circular contour, due to the groove 39terminating inwardly thereof, and which face serves to evenly displaceair escapin from the chamber 42 through the passage with the result thatthe plunger is urged towards centralization within the sleeve during itsmovement towards the plug. Owing to the relatively small size of thepassage, retarding the escape of air from the chamber, the plunger tendsto compress air therein,to the extent of establishing a fluid resistancewhich reacts to counteract vibratory reciprocation of the plunger whenthe solenoid is deenergized. By thus counteracting vibratoryreciprocation of the plunger together with the aforementionedcentralization thereof. and the precluding of rotation by theinterlocking pin wear on the sleeve by the plunger is appreciablyminimized thereby prolonging the effective use or life of the sleeve andeliminating noise or chatter heretofore occasioned by vibration.

The flanges i2 and 22 are provided with registering openings 43 for thereception of screws (not shown) whereby the solenoid may be securedtoanother device (not shown) with which it may be operativelyassociated, for example, an engine starter of the character wherein theend section 40 of the plunger 35 engages-a radially outstanding lug N6of a brush ring II I for maintainingthe ring ill, in a latched positionafter: the ring has been tripped and the end Ell disposed in sidewiseengagement with the lug Ht.

Without further elaboration the foregoing will so-fully explain theinvention that others may, by applying current knowledge, readily adaptthe same for use under various conditions of service. Moreover, it isnot indispensable that all the features of the invention be usedconjointly, since they may be employed advantageously in variouscombinations and sub-combinations.

It is obvious that the invention is not confined to the herein describeduse therefor as it may be utilized for any purpose to which it isadaptable. It is therefore to be understood that the invention is notlimited to-the specific construction as illustrated and described as thesame is only illustrative of the principles of operation, which arecapable of extended application in various forms, and that the inventioncomprehends all construction within the scope of the appended claims.

What is claimed is:

1. In a solenoid construction, a casing, a ma netic plug disposed withinand fixed tosaid casing, a coil assembly disposed Within said casing andcomprising a closure plate 'for said casing and being formed with acentrally disposed opening, a nonmagnetic sleeve having an open endextending into said opening and fixed to said plate and the other endremovably embracing end face disposed in confronting relation with saidplug and movable Within said sleeve towards said plug when said assemblyis rendered effec-' tive,and urged away from said plug when saidassembly is rendered ineffective and to thus provide an air chamberbetween said plunger and plug, the circumferential face of said plungerbeingformed with a longitudinal groove termi nating' inwardly of saidinner endface and receiving said portion of said pin to precluderelative rotation of said plunger and sleeve, said inner end face beingof a diameter and of a. circular contour to establish a relatively smallpassage between said plunger and sleeve for retarding the escape of airfrom said chamber occasioned by vibratory reciprocation of said plungerwhen said coil assembly has been rendered ineffective and for urgingcentralization of said plunger within said sleeve by the action of theescaping air during movement of the plunger toward said plug when saidcoil assembly has been rendered effective,

2. In a solenoid construction, a casing having an open end and formed atthe opposite end with an end wall, a magnetic plug axially disposedwithin said casing and fixed to said wall, a coil assembly disposedwithin said casing andvcomprising a closure plate transversing said openendv of said casing and being formed with a centrally disposed openingand an outwardly disposed rib surrounding said opening, a nonmagneticsleeve axis of the casing and extending through said rib and the face ofsaidopen end of said sleeveto preclude relative rotation therebetween,said pin having a side portion projecting within the bore of the sleeve,a magnetic cylindrical plunger having an inner end face disposed inconfrontingrelation with said plug and movable within said sleevetowards said plug when said assembly is rendered effective, a springinterposed between .said plunger and plug for urging said plunger 0 awayfrom said plug .when said assembly is rendered ineffective and to thusprovide an air chamber between said plunger and plug," thecircumferential face of said plunger being formed with a longitudinalgroove terminating inwardly of said inner end face and receiving saidportion of said pin to preclude relative rotation of said plunger andsleeve, said inner end face being of a diameter and of a circularcontour to establish a relatively small passage between said plunger andsleeve for retarding the escape of air from said chamber occasioned byvibratory reciprocation of said plunger when said coil assembly has beenrendered ineffective and for urging centralization of said plungerwithin said sleeve by the action of the escaping air during movement ofthe plunger toward said plug when said coil assembly has been renderedeflective.

3. In a solenoid construction, a casing; a plug of magnetic materialaxially disposed within said casing and secured at one end to thelatter; a coil assembly disposed within said casing and comprising aplate at one end of said casing, said plate having a central opening inaxial alignment with said plug and an outwardly projecting openingencircling boss; a sleeve of non-magnetic material axially disposedwithin said coil assembly, said sleeve having one end projecting intothe central opening and secured to said plate 'while the other end isremovably mounted on the free end of said plug to effect relativecentralization; an energizing coil mounted on said sleeve; a plunger ofmagnetic material slidably mounted in the other end of said sleeve andmovable towards said plug when said assembly is rendered eflective; aspring interposed between said plug and plunger for urging the latteraway from said plug when said assembly is rendered ineffective, saidplunger and sleeve being formed relatively of such diameters as todecelerate the flow of air therebetween for dampening vibratoryreciprdcations of said plunger when said coil assembly is renderedineffective; and a locking pin disposed in parallel relation to the axisof said casing and extending longitudinally through the encircling bosson said plate, said pin having one portion secured to the latter andanother portion projecting through said sleeve into said boss, thecircumferential face of said plunger being formed with a longitudinalgroove terminating inwardly from the outer end of said plunger andreceiving said pin projecting portion to preclude relative rotation ofsaid plunger and sleeve.

4. In a solenoid construction, a casing; a plug of magnetic material insaid casing and secured at one end to the latter; acoil assembly in saidcasing including a plate at one end of said casing, said plate having acentral opening; a sleeve of non-magnetic material disposed within saidcoil assembly, said sleeve having one end projecting into the centralopening and secured to said plate while the other end is removablymounted on the free end of said plug to efi'ect relative centralization;an energizing coil mounted on said sleeve; a plunger of magneticmaterial slidably mounted in the other end of said sleeve and movabletowards said plug when said assembly is rendered effective; a springinterposed between said-plug and plunger for urging the latter away fromsaid plug when said assembly is rendered inefiective, said plunger andsleeve being formed relatively of such diameters as to decelerate theflow of air therebetween for dampening vibratory reciprocations of saidplunger-when said coil assembly is rendered ineffective; and a lockingpin disposed in parallel relation to the axis of said casing andextending longitudinally through said plate, said pin having one portionsecured to the latter and another portion projecting through said sleeveinto said boss, the circumferential face of said plunger being formedwith a longitudinal groove terminating inwardly from the outer end ofsaid plunger and receiving said pin projecting portion to precluderelative rotation of said plunger and sleeve.

LOUIS FUCHS.

REFERENCES CITED The following references are of record in the file ofthis patent: UNITED STATES PATENTS Claytor July 7, 1942

